A sprayer device of the prior art is described in the U.S. Pat. No. 3,478,935 granted on 18 Nov. 1969 to Brooks. Said device does not serve the function of covering the micro-pump, but only activating it. It has a trigger hinged to a base element, which in turn is fastened to the ring nut of any pump of those commonly used at the time, the ring nut serving the purpose of applying the pump on a container of liquid to be nebulised, as well as covering said container. In particular, the device of U.S. Pat. No. 3,478,935 is constructed in a single piece of plastic material and it comprises an upper element and a lower element connected by a so-called virtual hinge obtained by means of thinning of the material that connects the upper element to the lower element. The upper element, including a trigger-shaped front portion, is provided superiorly with a cam portion able to act on the vertical activation pushbutton of the pump. The lower portion of the device is in a single piece with a cylindrical body for insertion by pressure on the aforesaid ring nut. The device of U.S. Pat. No. 3,478,935 lacks locking means to prevent the accidental activation of the trigger device and a safety seal that can prove that the device has been used and the liquid has been nebulised. European patent application No. 1 568 417 filed 18 Feb. 2005 by L'Oreal has, among its objects, that of providing a device for activating a pump push-button that can be adapted to every type of nebuliser pump with a greater ease of removal than provided by U.S. Pat. No. 3,478,935. The patent application by L'Oreal solves this problem with a device provided with a supporting ring having a portion for engaging the container, which portion extends only on a part of the periphery of the supporting ring. The device by L'Oreal is further provided with locking means against accidental activation in the form of a tab hinged in an inner part of the trigger and capable of serving as a sprag against a part of its same supporting ring to prevent the activation of the trigger.
Locking means against accidental activation during transport and shipment, similar to those described above, are provided in the nebuliser equipped with trigger described in the Japanese document No. 09-038540 published 10 Feb. 1997.
In this latter nebuliser an oscillating plate is hinged on a supporting ring and it is capable of going to abut against an inner part of the trigger provided with means to hold the oscillating plate, thereby preventing the activation of the trigger.
The aforementioned trigger locking means are not very reliable in assuring an effective locking, especially when the container is being handled. The locking tab or the oscillating plate, in a word the member that should prevent rotation, acts directly on the trigger itself and its stability and hence locking continuity are highly influenced by vibrations and oscillations of the trigger.
Moreover, neither in the device of the patent application No. 1 568 417, nor in the Japanese document No. 09-038540 are assurance means provided which could prove that the nebuliser micro-pump has actually been used.